ANALOGICTECH AAT2505IWP-AO-T1

AAT2505
Dual Channel, Step-Down
Converter/Linear Regulator
General Description
Features
The AAT2505 is a member of AnalogicTech's Total
Power Management IC™ (TPMIC™) product family. It is a low dropout (LDO) linear regulator and a
step-down converter with an input voltage range of
2.7V to 5.5V, making it ideal for applications with
single cell lithium-ion / polymer batteries.
•
•
The LDO has an independent input pin and is capable of delivering up to 300mA of current. The linear
regulator has been designed for high-speed turn-on
and turn-off performance, fast transient response,
and good power supply rejection ratio (PSRR).
Other features include low quiescent current, low
dropout voltage, and a Power-OK (POK) open drain
output signaling when VOUT is in regulation.
The 600mA step-down converter is designed to
operate with 1.4MHz of switching frequency, minimizing external component size and cost while
maintaining a low 27µA no load quiescent current.
Peak current mode control with internal compensation provides a stable converter with a low equivalent series resistance (ESR) ceramic output
capacitor for extremely low output ripple.
For maximum battery life with high voltage outputs,
the step-down converter duty cycle increases to
100%. The output voltage is either fixed or adjustable
with an integrated P- and N-channel MOSFET power
stage and 1.4MHz switching frequency.
The AAT2505 is available in a Pb-free, 12-pin
TDFN33 package and is rated over a temperature
range of -40°C to +85°C.
SystemPower™
VIN Range: 2.7V to 5.5V
300mA LDO
— 400mV Dropout Voltage at 300mA
— High Accuracy: ±1.5%
— Fast Line / Load Transient Response
— Power OK Output
600mA Step-Down Converter
— Up To 98% Efficiency
— 27µA No Load Quiescent Current
— Shutdown Current <1µA
— Low RDS(ON) Integrated Power Switches
— Fast Turn-On Time (150µs Typical)
— Low Dropout 100% Duty Cycle
— 1.4MHz Switching Frequency
— Internal Soft Start
Over-Temperature and Current Limit
Protection
TDFN33-12 Package
-40°C to +85°C Temperature Range
•
•
•
•
Applications
•
•
•
•
•
•
Cellular Phones
Digital Cameras
Handheld Instruments
Microprocessor/DSP Core/IO Power
PDAs and Handheld Computers
Portable Media Players
Typical Application
Efficiency
VIN = 2.7V to 5.5V
(VOUT = 2.5V; L = 6.8µH)
3
5
3.3V at 300mA
9
6
R3 100kΩ
7
8
C4
2.2µF
VP
VCC
VLDO
EN
ENLDO
LX
OUT
FB
POK
SGND
GND
PGND
100
4
2.5V at 600mA
10
L1
2
11
6.8µH
12
1
C1
4.7µF
Efficiency (%)
C3
10µF
90
VIN = 3.3V
80
70
U1
AAT2505
60
0.1
L1 Sumida CDRH3D16-4R7 C1 Murata GRM219R61A475KE19
C3 Murata GRM21BR60J106KE19
2505.2006.06.1.1
1
10
100
1000
Output Current (mA)
1
AAT2505
Dual Channel, Step-Down
Converter/Linear Regulator
Pin Descriptions
Pin #
Symbol
1
PGND
2
3
4
5
6
LX
VP
VCC
VLDO
OUT
7
POK
8
9
GND
ENLDO
10
EN
11
FB
12
SGND
EP
Function
Step-down converter power ground return pin. Connect to the output and input capacitor
return. See section on PCB layout guidelines and evaluation board layout diagram.
Power switching node. Output switching node that connects to the output inductor.
Step-down converter power stage supply voltage. Must be closely decoupled to PGND.
Step-down converter bias supply. Connect to VP.
LDO input voltage; should be decoupled with 1µF or greater capacitor.
300mA LDO output pin. A 2.2µF or greater output low-ESR ceramic capacitor is required
for stability.
Power-OK output for the LDO. This open drain output is low when the OUT is out of regulation. Connect a pull-up resistor from POK to OUT or VLDO. When LDO is in shutdown
(ENLDO = 0V), POK is pulled low.
LDO ground connection pin.
Enable pin for LDO. When connected low, LDO is disabled and consumes less than 1µA
of current.
Step-down converter enable. When connected low, the step-down converter is disabled
and consumes less than 1µA.
Step-down converter feedback input pin. For fixed output voltage versions, this pin is connected to the converter output, forcing the converter to regulate to the specific voltage.
For adjustable output versions, an external resistive divider ties to this point and programs
the output voltage to the desired value.
Step-down converter signal ground. For external feedback, return the feedback resistive
divider to this ground. For internal fixed version, tie to the point of load return. See section on PCB layout guidelines and evaluation board layout diagram.
Exposed paddle (bottom). Use properly sized vias for thermal coupling to the ground
plane. See section on PCB layout guidelines.
Pin Configuration
TDFN33-12
(Top View)
PGND
LX
VP
VCC
VLDO
OUT
2
1
12
2
11
3
10
4
9
5
8
6
7
SGND
FB
EN
ENLDO
GND
POK
2505.2006.06.1.1
AAT2505
Dual Channel, Step-Down
Converter/Linear Regulator
Absolute Maximum Ratings1
Symbol
Description
VP, VLDO
VLX
VFB
VEN
TJ
TLEAD
Input Voltages to GND
Lx to GND
FB to GND
EN to GND
Operating Junction Temperature Range
Maximum Soldering Temperature (at leads, 10 sec)
Value
Units
6.0
-0.3 to VP + 0.3
-0.3 to VP + 0.3
-0.3 to 6.0
-40 to 150
300
V
V
V
V
°C
°C
Value
Units
2.0
50
W
°C/W
Thermal Information
Symbol
PD
θJA
Description
Maximum Power Dissipation
Thermal Resistance2
1. Stresses above those listed in Absolute Maximum Ratings may cause permanent damage to the device. Functional operation at conditions other than the operating conditions specified is not implied. Only one Absolute Maximum Rating should be applied at any one time.
2. Mounted on an FR4 board with exposed paddle connected to ground plane.
2505.2006.06.1.1
3
AAT2505
Dual Channel, Step-Down
Converter/Linear Regulator
Electrical Characteristics1
VIN = VLDO = VOUT(NOM) + 1V for VOUT options greater than 1.5V. VIN = VLDO = 2.5V for VOUT ≤ 1.5V. IOUT = 1mA,
COUT = 2.2µF, CIN = 1µF, TA = -40°C to +85°C, unless otherwise noted. Typical values are TA = 25°C.
Symbol
Description
Conditions
Output Voltage Tolerance
IOUT = 1mA
to 300mA
Min
Typ
Max
Units
1.5
2.5
%
5.5
V
600
mV
0.09
%/V
LDO
VOUT
VIN
TA = 25°C
TA = -40°C to +85°C
Input Voltage
VDO
ΔVOUT/
VOUT* VIN
Dropout Voltage3, 4
IOUT = 300mA
Line Regulation
VIN = VOUT + 1V to 5V
ΔVOUT(Line)
Dynamic Line Regulation
ΔVOUT(Load)
IOUT
ISC
IQLDO
VPOK
VPOKHYS
VPOK(OL)
IPOK
Dynamic Load Regulation
Output Current
Short-Circuit Current
LDO Quiescent Current
POK Trip Threshold
POK Hysteresis
POK Output Voltage Low
POK Output Leakage Current
ISHDN
Shutdown Current
PSRR
Power Supply Rejection Ratio
TSD
THYS
eN
TC
Over-Temperature Shutdown
Threshold
Over-Temperature Shutdown
Hysteresis
Output Noise
Output Voltage Temperature
Coefficient
IOUT = 300mA, VIN = VOUT + 1V
to VOUT + 2V, TR/TF = 2µs
IOUT = 1mA to 300mA, TR <5µs
VOUT > 1.3V
VOUT < 0.4V
VIN = 5V, No Load, ENLDO = VIN
VOUT Rising, TA = 25°C
ISINK = 1mA
VPOK < 5.5V, VOUT in Regulation
VIN = 5V; ENLDO = GND,
EN = SGND = PGND
1kHz
IOUT = 10mA
10kHz
1MHz
-1.5
-2.5
VOUT +
VDO2
400
2.5
mV
60
0.4
1.0
mV
mA
A
µA
% of VOUT
% of VOUT
V
µA
1.0
µA
300
90
1
70
94
1.0
125
98
65
45
42
dB
145
°C
15
°C
250
µVRMS
22
ppm/°C
1. The AAT2505 is guaranteed to meet performance specifications over the -40°C to +85°C operating temperature range and is assured
by design, characterization, and correlation with statistical process controls.
2. To calculate the minimum LDO input voltage, use the following equation: VIN(MIN) = VOUT(MAX) + VDO(MAX), as long as VIN ≥ 2.5V.
3. For VOUT < 2.1V, VDO = 2.5 - VOUT.
4. VDO is defined as VIN - VOUT when VOUT is 98% of nominal.
4
2505.2006.06.1.1
AAT2505
Dual Channel, Step-Down
Converter/Linear Regulator
Electrical Characteristics1
IOUT = 600mA; typical values are TA = 25°C, VIN = VCC = VP = 3.6V.
Symbol
Description
Conditions
Buck Converter
VIN
Input Voltage
VUVLO
UVLO Threshold
VOUT
Output Voltage Tolerance
VOUT
IQBUCK
Output Voltage Range
Step-Down Converter
Quiescent Current
ISHDN
Shutdown Current
ILIM
RDS(ON)H
RDS(ON)L
ILXLK
ΔVLinereg
Line Regulation
VFB
FB Threshold Voltage Accuracy
IFB
RFB
FB Leakage Current
FB Impedance
TS
Start-Up Time
FOSC
TSD
THYS
Oscillator Frequency
Over-Temperature Shutdown
Threshold
Over-Temperature Shutdown
Hysteresis
Logic Signals
VEN(L)
Enable Threshold Low
VEN(H)
Enable Threshold High
IEN(H)
Leakage Current
Typ
Max
Units
5.5
2.7
V
V
mV
V
-3.0
3.0
%
0.6
VIN
V
70
µA
1.0
µA
2.7
VIN Rising
Hysteresis
VIN Falling
IOUT = 0 to 600mA,
VIN = 2.7V to 5.5V
100
1.8
ENLDO = GND, No Load,
0.6V Adjustable Version
EN = SGND = PGND,
ENLDO = GND
P-Channel Current Limit
High Side Switch On Resistance
Low Side Switch On Resistance
LX Leakage Current
Min
27
800
mA
Ω
Ω
0.45
0.40
VIN = 5.5V, VLX = 0 to VIN,
EN = SGND = PGND
VIN = 2.7V to 5.5V
0.6V Output, No Load,
TA = 25°C
0.6V Output
> 0.6V Output
From Enable to Output
Regulation
TA = 25°C
1.0
0.1
591
600
%/V
609
mV
0.2
µA
kΩ
250
150
1.0
1.4
µs
2.0
MHz
140
°C
15
°C
0.6
1.4
-1.0
µA
1.0
V
V
µA
1. The AAT2505 is guaranteed to meet performance specifications over the -40°C to +85°C operating temperature range and is assured
by design, characterization, and correlation with statistical process controls.
2505.2006.06.1.1
5
AAT2505
Dual Channel, Step-Down
Converter/Linear Regulator
Typical Characteristics
Unless otherwise noted, VIN = 5V, TA = 25°C.
LDO Dropout Characteristics
LDO Dropout Voltage vs. Temperature
(EN = GND; ENLDO = VIN)
(EN = GND; ENLDO = VIN)
3.20
IL = 300mA
480
Output Voltage (V)
Dropout Voltage (mV)
540
420
360
300
IL = 100mA
IL = 150mA
240
180
120
60
-40 -30 -20 -10 0
IOUT = 0mA
2.80
IOUT = 300mA
IOUT = 150mA
2.60
2.40
2.20
IL = 50mA
0
3.00
IOUT = 10mA
2.00
2.70
10 20 30 40 50 60 70 80 90 100 110 120
2.80
LDO Dropout Voltage vs. Output Current
3.10
3.20
3.30
(EN = GND; ENLDO = VIN)
90.00
500
Ground Current (μA)
450
Dropout Voltage (mV)
3.00
LDO Ground Current vs. Input Voltage
(EN = GND; ENLDO = VIN)
400
350
300
85°C
250
200
25°C
150
-40°C
100
80.00
70.00
60.00
IOUT=300mA
50.00
IOUT=150mA
IOUT=50mA
40.00
IOUT=0mA
30.00
IOUT=10mA
20.00
10.00
50
0
0.00
0
50
100
150
200
250
300
2
2.5
3
3.5
4
4.5
5
Input Voltage (V)
Output Current (mA)
Output Voltage Variation (%)
2.90
Input Voltage (V)
Temperature (°C)
LDO Output Voltage vs. Temperature
LDO Initial Power-Up Response Time
(EN = GND; ENLDO = VIN)
(EN = GND; ENLDO = VIN)
0.05
0.00
VENLDO (5V/div)
-0.05
-0.10
-0.15
-0.20
-0.25
-0.30
-0.35
-0.40
-0.45
-40 -30 -20 -10
0
10
20
30
40
50
60
Temperature (°°C)
6
IOUT = 100mA
IOUT = 50mA
70
80
90 100
VOUT (1V/div)
Time (400µs/div)
2505.2006.06.1.1
AAT2505
Dual Channel, Step-Down
Converter/Linear Regulator
Typical Characteristics
Unless otherwise noted, VIN = 5V, TA = 25°C.
LDO Turn-Off Response Time
LDO Turn-On Time From Enable (VIN present)
(EN = GND; ENLDO = VIN)
(EN = GND; ENLDO = VIN)
VENLDO (5V/div)
VENLDO = 5V/div
VOUT (1V/div)
VOUT = 1V/div
Time (50µs/div)
Time (5µs/div)
LDO Line Transient Response
LDO Load Transient Response
(EN = GND; ENLDO = VIN)
(EN = GND; ENLDO = VIN)
Input Voltage (V)
3.03
2.85
4
3.02
3
3.01
2
3.00
VOUT
1
2.99
0
2.98
500
400
VOUT
2.80
300
2.75
200
2.70
100
2.65
0
Output Current (mA)
2.90
Output Voltage (V)
VIN
3.04
Output Voltage (V)
6
5
VIN = 4V
IOUT
2.60
-100
Time (100µs/div)
Time (100µs/div)
LDO Load Transient Response 300mA
3.00
800
2.90
700
2.80
2.70
600
VOUT
500
2.60
400
2.50
300
2.40
200
2.30
100
IOUT
2.20
0
2.10
-100
Output Current (mA)
Output Voltage (V)
(EN = GND; ENLDO = VIN)
Time (10µs/div)
2505.2006.06.1.1
7
AAT2505
Dual Channel, Step-Down
Converter/Linear Regulator
Typical Characteristics
Unless otherwise noted, VIN = 5V, TA = 25°C.
LDO Over-Current Protection
LDO ENLDO vs. VIN
(EN = GND; ENLDO = VIN)
Output Current (mA)
1200
1.250
1000
1.225
800
1.200
VIH
1.175
600
1.150
400
1.125
200
VIL
1.100
0
1.075
1.050
2.5
-200
Time (50ms/div)
3.0
3.5
4.0
4.5
5.0
5.5
Input Voltage (V)
Step-Down Converter Efficiency vs. Load
Step-Down Converter DC Regulation
(VOUT = 3.3V; L = 10μ
μH; ENLDO = GND)
(VOUT = 3.3V; L = 6.8µH; ENLDO = GND)
1.0
90
Output Error (%)
Efficiency (%)
100
VIN = 3.9V
VIN = 4.2V
80
70
VIN = 5.0V
0.5
0.0
VIN = 4.2V
-0.5
-1.0
60
0.1
1
10
100
0.1
1000
1
Output Current (mA)
10
100
1000
Output Current (mA)
Step-Down Converter Efficiency vs. Load
Step-Down Converter DC Regulation
(VOUT = 2.5V; L = 10μ
μH; ENLDO = GND)
(VOUT = 2.5V; L = 6.8µH; ENLDO = GND)
1.0
100
Output Error (%)
Efficiency (%)
VIN = 3.3V
90
VIN = 3.0V
VIN = 3.6V
80
70
VIN = 4.2V
0.0
VIN = 3.6V
-0.5
VIN = 3.0V
-1.0
60
0.1
1
10
Output Current (mA)
8
VIN = 5.0V
0.5
100
1000
0.1
1
10
100
1000
Output Current (mA)
2505.2006.06.1.1
AAT2505
Dual Channel, Step-Down
Converter/Linear Regulator
Typical Characteristics
Unless otherwise noted, VIN = 5V, TA = 25°C.
Step-Down Converter Efficiency vs. Load
Step-Down Converter DC Regulation
(VOUT = 1.5V; L = 4.7μ
μH; ENLDO = GND)
(VOUT = 1.8V; L = 4.7µH; ENLDO = GND)
1.0
100
VIN = 2.7V
80
Output Error (%)
Efficiency (%)
90
VIN = 3.6V
VIN = 4.2V
70
60
50
0.1
1
10
100
1000
0.5
VIN = 4.2V
0.0
VIN = 3.6V
-0.5
VIN = 2.7V
-1.0
0.1
1
Output Current (mA)
1000
Step-Down Converter
Frequency vs. Input Voltage
Step-Down Converter
Output Voltage Error vs. Temperature
(VOUT = 1.8V; EN = VIN; ENLDO = GND)
(VIN = 3.6V; VO = 1.5V; EN = VIN; ENLDO = GND)
2.0
Output Error (%)
0.5
0.0
-0.5
-1.0
-1.5
-2.0
1.0
0.0
-1.0
-2.0
2.7
3.1
3.5
3.9
4.3
4.7
5.1
5.5
-40
-20
0
20
40
60
80
Step-Down Converter
Switching Frequency vs. Temperature
Step-Down Converter
Input Current vs. Input Voltage
(VIN = 3.6V; VO = 1.5V; EN = VIN; ENLDO = GND)
(VO = 1.8V; EN = VIN; ENLDO = GND)
35
15.0
Input Current (μ
μA)
12.0
9.0
6.0
3.0
0.0
-3.0
-6.0
-9.0
85°C
30
25°C
25
20
-12.0
-15.0
-40
100
Temperature (°°C)
Input Voltage (V)
Frequency Variation (%)
100
Output Current (mA)
1.0
Frequency Variation (%)
10
-40°C
15
-20
0
20
40
Temperature (°°C)
2505.2006.06.1.1
60
80
100
2.5
3.0
3.5
4.0
4.5
5.0
5.5
Input Voltage (V)
9
AAT2505
Dual Channel, Step-Down
Converter/Linear Regulator
Typical Characteristics
Unless otherwise noted, VIN = 5V, TA = 25°C.
Step-Down Converter
P-Channel RDS(ON) vs. Input Voltage
Step-Down Converter
N-Channel RDS(ON) vs. Input Voltage
(EN = VIN; ENLDO = GND)
(EN = VIN; ENLDO = GND)
750
750
700
700
120°C
650
100°C
RDS(ON) (mΩ
Ω)
RDS(ON) (mΩ
Ω)
650
600
550
85°C
500
450
25°C
400
120°C
100°C
600
550
500
85°C
450
400
25°C
350
350
300
300
2.5
3 .0
3.5
4 .0
4.5
5 .0
2.5
5.5
3 .0
3.5
4 .0
4.5
5 .0
5.5
Input Voltage (V)
Input Voltage (V)
(1mA to 300mA; VIN = 3.6V; VOUT = 2.5V;
C1 = 4.7µF; ENLDO = GND)
1.6
1.8
1.4
1.7
1.2
1.6
1.0
1.5
0.8
1.4
0.6
1.3
0.4
1.2
0.2
1.1
0.0
1.0
-0.2
2.9
1.8
2.7
1.6
2.5
1.4
2.3
1.2
2.1
1.0
1.9
0.8
1.7
0.6
1.5
0.4
1.3
0.2
1.1
0.0
0.9
-0.2
Time (50µs/div)
Load and Inductor Current
(200mA/div) (bottom)
1.8
1.9
Load and Inductor Current
(200mA/div) (bottom)
2.0
Output Voltage
(top) (V)
Step-Down Converter Load Transient Response
(1mA to 300mA; VIN = 3.6V; VOUT = 1.8V;
C1 = 4.7µF; ENLDO = GND)
Output Voltage
(top) (V)
Step-Down Converter Load Transient Response
Time (50µs/div)
Step-Down Converter Line Transient
Step-Down Converter Line Regulation
(VOUT = 1.8V @ 400mA)
(VOUT = 1.8V)
1.84
7.6
1.82
6.6
0.40
5.6
1.78
4.6
1.76
3.6
1.74
2.6
Accuracy (%)
1.80
Input Voltage
(bottom) (V)
Output Voltage
(top) (V)
0.30
0.20
IOUT = 10mA
0.10
0.00
IOUT = 1mA
-0.10
IOUT = 400mA
-0.20
-0.30
-0.40
2.5
3.0
3.5
4.0
4.5
5.0
5.5
6.0
Time (25µs/div)
Input Voltage (V)
10
2505.2006.06.1.1
AAT2505
Dual Channel, Step-Down
Converter/Linear Regulator
Typical Characteristics
Step-Down Converter Output Ripple
(VIN = 3.6V; VOUT = 1.8V; 400mA;
EN = VIN; ENLDO = GND)
(VIN = 3.6V; VOUT = 1.8V; 400mA;
EN = VIN; ENLDO = GND)
5.0
4.0
1.6
VEN
VO
1.4
1.2
2.0
1.0
1.0
0.8
0.0
0.6
-1.0
0.4
-2.0
0.2
-3.0
IL
0.0
-4.0
-0.2
-5.0
-0.4
μs/div)
Time (100μ
2505.2006.06.1.1
40
0.9
20
0.8
0
0.7
-20
0.6
-40
0.5
-60
0.4
-80
0.3
-100
0.2
Inductor Current
(bottom) (A)
3.0
Output Voltage (AC Coupled)
(top) (mV)
Step-Down Converter Soft Start
Inductor Current
(bottom) (A)
Enable and Output Voltage
(top) (V)
Unless otherwise noted, VIN = 5V, TA = 25°C.
0.1
-120
Time (250ns/div)
11
AAT2505
Dual Channel, Step-Down
Converter/Linear Regulator
Functional Block Diagram
VCC
FB
VP
Error
Amp.
DH
See
Note
LX
Logic
Voltage
Reference
DL
Control
Logic
EN
PGND
SGND
OUT
VLDO
Over-Current
Protection
Error
Amp.
ENLDO
Fast Start
Control
POK
Voltage
Reference
94%
+
-
GND
Note: Internal resistor divider included for ≥ 1.2V versions. For low voltage versions, the feedback pin is tied directly to the error amplifier input.
Functional Description
The AAT2505 is a high performance power management IC comprised of a buck converter and a
linear regulator. The high efficiency buck converter is capable of delivering up to 600mA. Designed
to operate at 1.4MHz, the converter requires only
three external components (CIN, COUT, and LX) and
is stable with a ceramic output capacitor. The linear regulator delivers 300mA and also is stable
with a ceramic output capacitor.
Linear Regulator
The advanced circuit design of the linear regulator
has been specifically optimized for very fast start-up
and shutdown timing. This proprietary CMOS LDO
has also been tailored for superior transient response
characteristics. These traits are particularly important
for applications that require fast power supply timing.
The high-speed turn-on capability is enabled
through implementation of a fast-start control cir12
cuit which accelerates the power-up behavior of
fundamental control and feedback circuits within
the LDO regulator. Fast turn-off time response is
achieved by an active output pull-down circuit,
which is enabled when the LDO regulator is placed
in shutdown mode. This active fast shutdown circuit has no adverse effect on normal device operation. The LDO regulator output has been specifically optimized to function with low-cost, low-ESR
ceramic capacitors; however, the design will allow
for operation over a wide range of capacitor types.
Other features include an integrated Power-OK
comparator which indicates when the output is out of
regulation. The POK open-drain output is low when
OUT is 6% below its nominal regulation voltage. The
open-drain signal is held low when the linear regulator is in shutdown mode. The regulator comes with
complete short-circuit and thermal protection. The
combination of these two internal protection circuits
gives a comprehensive safety system to guard
against extreme adverse operating conditions.
2505.2006.06.1.1
AAT2505
Dual Channel, Step-Down
Converter/Linear Regulator
The regulator features an enable/disable function.
This pin (ENLDO) is active high and is compatible
with CMOS logic. To assure the LDO regulator will
switch on, the ENLDO turn-on control level must be
greater than 1.5V. The LDO regulator will go into the
disable shutdown mode when the voltage on the EN
pin falls below 0.6V. If the enable function is not
needed in a specific application, it may be tied to VIN
to keep the LDO regulator in a continuously on state.
When the regulator is in shutdown mode, an internal 20kΩ resistor is connected between OUT and
GND. This is intended to discharge COUT when the
LDO regulator is disabled. The internal 20kΩ resistor has no adverse impact on device turn-on time.
Step-Down Converter
The AAT2505 buck is a constant frequency peak
current mode PWM converter with internal compensation. It is designed to operate with an input voltage
range of 2.7V to 5.5V. The output voltage ranges
from 0.6V to the input voltage for the internally fixed
version (see Figure 1) , and up to 3.3V for the externally adjustable version (see Figure 2). The 0.6V
fixed model is also the adjustable version and is
externally programmable with a resistive divider. The
converter MOSFET power stage is sized for 600mA
load capability with up to 96% efficiency. Light load
efficiency exceeds 80% at a 500µA load.
Soft Start
The AAT2505 soft-start control prevents output
voltage overshoot and limits inrush current when
VIN
Low Dropout Operation
For conditions where the input voltage drops to the
output voltage level, the converter duty cycle
increases to 100%. As 100% duty cycle is
approached, the minimum off-time initially forces
the high side on-time to exceed the 1.4MHz clock
cycle and reduce the effective switching frequency.
Once the input drops below the level where the output can be regulated, the high side P-channel
MOSFET is turned on continuously for 100% duty
cycle. At 100% duty cycle, the output voltage tracks
the input voltage minus the IR drop of the high side
P-channel MOSFET RDS(ON).
Low Supply
The under-voltage lockout (UVLO) guarantees sufficient VIN bias and proper operation of all internal
circuitry prior to activation.
Fault Protection
For overload conditions, the peak inductor current is
limited. Thermal protection disables switching when
the internal dissipation or ambient temperature
becomes excessive. The junction over-temperature
threshold is 140°C with 15°C of hysteresis.
VIN
C3
10µF
3
5
9
VOUTLDO
6
7
C4
4.7µF
either the input power or the enable input is
applied. When pulled low, the enable input forces
the converter into a low-power, non-switching state
with a bias current of less than 1µA. A startup time
of 150µs is achieved across the operating range.
R3
100kΩ
8
VP
VLDO
VCC
EN
ENLDO
LX
OUT
FB
POK
SGND
GND
PGND
C3
10µF
4
2
11
L1
VOUTBUCK
9
VOUTLDO
4.7µH
6
7
12
1
U1
AAT2505
Figure 1: AAT2505 Fixed Output.
2505.2006.06.1.1
3
5
10
C1
4.7µF
C4
4.7µF
R3
100kΩ
8
VP
VCC
VLDO
EN
ENLDO
LX
OUT
FB
POK
SGND
GND
PGND
U1
AAT2505
4
10
2
11
VOUTBUCK
L1
4.7µH
R1
12
1
C8
100pF
R2
59k
C1
4.7µF
Figure 2: AAT2505 with Adjustable Step-Down
Output and Enhanced Transient Response.
13
AAT2505
Dual Channel, Step-Down
Converter/Linear Regulator
Applications Information
Linear Regulator
Input and Output Capacitors: An input capacitor
is not required for basic operation of the linear regulator. However, if the AAT2505 is physically located more than three centimeters from an input
power source, a CIN capacitor will be needed for
stable operation. Typically, a 1µF or larger capacitor is recommended for CIN in most applications.
CIN should be located as closely to the device VIN
pin as practically possible.
An input capacitor greater than 1µF will offer superior input line transient response and maximize
power supply ripple rejection. Ceramic, tantalum,
or aluminum electrolytic capacitors may be selected for CIN. There is no specific capacitor ESR
requirement for CIN. However, for 300mA LDO regulator output operation, ceramic capacitors are recommended for CIN due to their inherent capability
over tantalum capacitors to withstand input current
surges from low impedance sources such as batteries in portable devices.
For proper load voltage regulation and operational
stability, a capacitor is required between OUT and
GND. The COUT capacitor connection to the LDO
regulator ground pin should be made as directly as
practically possible for maximum device performance. Since the regulator has been designed to
function with very low ESR capacitors, ceramic
capacitors in the 1.0µF to 10µF range are recommended for best performance. Applications utilizing
the exceptionally low output noise and optimum
power supply ripple rejection should use 2.2µF or
greater for COUT. In low output current applications,
where output load is less than 10mA, the minimum
value for COUT can be as low as 0.47µF.
Equivalent Series Resistance: ESR is a very
important characteristic to consider when selecting a
capacitor. ESR is the internal series resistance associated with a capacitor that includes lead resistance,
internal connections, size and area, material composition, and ambient temperature. Typically, capacitor
ESR is measured in milliohms for ceramic capacitors and can range to more than several ohms for
tantalum or aluminum electrolytic capacitors.
14
Ceramic Capacitor Materials: Ceramic capacitors
less than 0.1µF are typically made from NPO or
C0G materials. NPO and C0G materials generally
have tight tolerance and are very stable over temperature. Larger capacitor values are usually composed of X7R, X5R, Z5U, or Y5V dielectric materials. Large ceramic capacitors (i.e., greater than
2.2µF) are often available in low-cost Y5V and Z5U
dielectrics. These two material types are not recommended for use with the regulator, since the
capacitor tolerance can vary more than ±50% over
the operating temperature range of the device. A
2.2µF Y5V capacitor could be reduced to 1µF over
temperature; this could cause problems for circuit
operation. X7R and X5R dielectrics are much more
desirable. The temperature tolerance of X7R dielectric is better than ±15%.
Capacitor area is another contributor to ESR.
Capacitors that are physically large in size will have
a lower ESR when compared to a smaller sized
capacitor of an equivalent material and capacitance value. These larger devices can improve circuit transient response when compared to an equal
value capacitor in a smaller package size. Consult
capacitor vendor datasheets carefully when selecting capacitors for LDO regulators.
Step-Down Converter
Inductor Selection: The step-down converter
uses peak current mode control with slope compensation to maintain stability for duty cycles
greater than 50%. The output inductor value must
be selected so the inductor current down slope
meets the internal slope compensation requirements. The internal slope compensation for the
adjustable and low-voltage fixed versions of the
AAT2505 is 0.24A/µsec. This equates to a slope
compensation that is 75% of the inductor current
down slope for a 1.5V output and 4.7µH inductor.
m=
0.75 ⋅ VO 0.75 ⋅ 1.5V
A
=
= 0.24
L
4.7μH
μsec
2505.2006.06.1.1
AAT2505
Dual Channel, Step-Down
Converter/Linear Regulator
This is the internal slope compensation for the
adjustable (0.6V) version or low-voltage fixed versions. When externally programming the 0.6V version to 2.5V, the calculated inductance is 7.5µH.
L=
0.75 ⋅ VO
=
m
=3
μsec
0.75 ⋅ VO
≈ 3 A ⋅ VO
A
0.24A μsec
Input Capacitor
Select a 4.7µF to 10µF X7R or X5R ceramic capacitor for the input. To estimate the required input
capacitor size, determine the acceptable input ripple level (VPP) and solve for C. The calculated
value varies with input voltage and is a maximum
when VIN is double the output voltage.
μsec
⋅ 2.5V = 7.5μH
A
CIN =
In this case, a standard 6.8µH value is selected.
For high-voltage fixed versions (2.5V and above),
m = 0.48A/µsec. Table 1 displays inductor values
for the AAT2505 fixed and adjustable options.
Manufacturer's specifications list both the inductor
DC current rating, which is a thermal limitation, and
the peak current rating, which is determined by the
saturation characteristics. The inductor should not
show any appreciable saturation under normal load
conditions. Some inductors may meet the peak and
average current ratings yet result in excessive losses due to a high DCR. Always consider the losses
associated with the DCR and its effect on the total
converter efficiency when selecting an inductor.
The 4.7µH CDRH3D16 series inductor selected
from Sumida has a 105mΩ DCR and a 900mA DC
current rating. At full load, the inductor DC loss is
17mW which gives a 2.8% loss in efficiency for a
400mA, 1.5V output.
Configuration
0.6V Adjustable With
External Feedback
Fixed Output
VOBUCK ⎛ VOBUCK⎞
· 1⎝
VIN
VIN ⎠
⎛ VPP
⎞
- ESR · FS
⎝ IOBUCK
⎠
⎞ 1
VOBUCK ⎛
V
· 1 - OBUCK = for VIN = 2 × VOBUCK
⎝
VIN
VIN ⎠ 4
CIN(MIN) =
1
⎛ VPP
⎞
- ESR · 4 · FS
⎝ IOBUCK
⎠
Always examine the ceramic capacitor DC voltage
coefficient characteristics when selecting the proper value. For example, the capacitance of a 10µF,
6.3V, X5R ceramic capacitor with 5.0V DC applied
is actually about 6µF.
The maximum input capacitor RMS current is:
IRMS = IOBUCK ·
⎞
VOBUCK ⎛
V
· 1 - OBUCK
⎝
VIN
VIN ⎠
Output Voltage
Inductor
1V, 1.2V
2.2µH
1.5V, 1.8V
4.7µH
2.5V, 3.3V
6.8µH
0.6V to 3.3V
4.7µH
Table 1: Inductor Values.
2505.2006.06.1.1
15
AAT2505
Dual Channel, Step-Down
Converter/Linear Regulator
The input capacitor RMS ripple current varies with
the input and output voltage and will always be less
than or equal to half of the total DC load current.
VOBUCK ⎛ VOBUCK⎞
· 1=
⎝
VIN
VIN ⎠
D · (1 - D) =
0.52 =
1
2
for VIN = 2 x VOBUCK
IRMS(MAX) =
VOBUCK
⎛
IOBUCK
2
VOBUCK⎞
· 1The term
appears in both the
⎝
VIN
VIN ⎠
input voltage ripple and input capacitor RMS current equations and is a maximum when VOBUCK is
twice VIN. This is why the input voltage ripple and
the input capacitor RMS current ripple are a maximum at 50% duty cycle.
The input capacitor provides a low impedance loop
for the edges of pulsed current drawn by the
AAT2505. Low ESR/ESL X7R and X5R ceramic
capacitors are ideal for this function. To minimize
stray inductance, the capacitor should be placed as
closely as possible to the IC. This keeps the high
frequency content of the input current localized,
minimizing EMI and input voltage ripple.
The proper placement of the input capacitor (C2)
can be seen in the evaluation board layout in
Figure 3.
Figure 3: AAT2505 Evaluation Board Top Side.
16
A laboratory test set-up typically consists of two
long wires running from the bench power supply to
the evaluation board input voltage pins. The inductance of these wires, along with the low-ESR
ceramic input capacitor, can create a high Q network that may affect converter performance. This
problem often becomes apparent in the form of
excessive ringing in the output voltage during load
transients. Errors in the loop phase and gain
measurements can also result.
Since the inductance of a short PCB trace feeding
the input voltage is significantly lower than the
power leads from the bench power supply, most
applications do not exhibit this problem.
In applications where the input power source lead
inductance cannot be reduced to a level that does
not affect the converter performance, a high ESR
tantalum or aluminum electrolytic should be placed
in parallel with the low ESR, ESL bypass ceramic.
This dampens the high Q network and stabilizes
the system.
Output Capacitor
The output capacitor limits the output ripple and
provides holdup during large load transitions. A
4.7µF to 10µF X5R or X7R ceramic capacitor provides sufficient bulk capacitance to stabilize the
output during large load transitions and has the
ESR and ESL characteristics necessary for low
output ripple.
Figure 4: AAT2505 Evaluation Board
Bottom Side.
2505.2006.06.1.1
AAT2505
Dual Channel, Step-Down
Converter/Linear Regulator
The output voltage droop due to a load transient is
dominated by the capacitance of the ceramic output capacitor. During a step increase in load current, the ceramic output capacitor alone supplies
the load current until the loop responds. Within two
or three switching cycles, the loop responds and
the inductor current increases to match the load
current demand. The relationship of the output voltage droop during the three switching cycles to the
output capacitance can be estimated by:
COUT =
3 · ΔILOAD
VDROOP · FS
Once the average inductor current increases to the
DC load level, the output voltage recovers. The
above equation establishes a limit on the minimum
value for the output capacitor with respect to load
transients.
The internal voltage loop compensation limits the
minimum output capacitor value to 4.7µF. This is
due to its effect on the loop crossover frequency
(bandwidth), phase margin, and gain margin.
Increased output capacitance will reduce the
crossover frequency with greater phase margin.
The maximum output capacitor RMS ripple current
is given by:
IRMS(MAX) =
1
VOUT · (VIN(MAX) - VOUT)
L · FS · VIN(MAX)
2· 3
·
Dissipation due to the RMS current in the ceramic
output capacitor ESR is typically minimal, resulting in
less than a few degrees rise in hot-spot temperature.
Adjustable Output Resistor Selection
For applications requiring an adjustable output voltage, the 0.6V version can be externally programmed. Resistors R1 and R2 of Figure 5 program
the output to regulate at a voltage higher than 0.6V.
2505.2006.06.1.1
To limit the bias current required for the external
feedback resistor string while maintaining good
noise immunity, the minimum suggested value for
R2 is 59kΩ. Although a larger value will further
reduce quiescent current, it will also increase the
impedance of the feedback node, making it more
sensitive to external noise and interference. Table 2
summarizes the resistor values for various output
voltages with R2 set to either 59kΩ for good noise
immunity or 221kΩ for reduced no load input current.
⎛ VOUT ⎞
⎛ 1.5V ⎞
R1 = V
-1 · R2 = 0.6V - 1 · 59kΩ = 88.5kΩ
⎝ REF ⎠
⎝
⎠
The adjustable version of the AAT2505, combined
with an external feedforward capacitor (C8 in
Figures 2 and 5), delivers enhanced transient
response for extreme pulsed load applications.
The addition of the feedforward capacitor typically
requires a larger output capacitor C1 for stability.
Ω
R2 = 59kΩ
Ω
R2 = 221kΩ
VOUT (V)
Ω)
R1 (kΩ
Ω)
R1 (kΩ
0.8
0.9
1.0
1.1
1.2
1.3
1.4
1.5
1.8
1.85
2.0
2.5
3.3
19.6
29.4
39.2
49.9
59.0
68.1
78.7
88.7
118
124
137
187
267
75
113
150
187
221
261
301
332
442
464
523
715
1000
Table 2: Adjustable Resistor Values For Use
With 0.6V Step-Down Converter.
17
AAT2505
Dual Channel, Step-Down
Converter/Linear Regulator
LX1
VOUTBUCK
C7
0.01µF
C1
4.7µF1
C2
10µF
U1
VIN1
3
4
3
2
1
5
6
LDO Input
C3
10µF
R1
Table 3
AAT2505
1
2
L1
Table 3
C9
n/a
PGND
SGND
LX
FB
VP
EN
VCC
ENLDO
IN
GND
OUT
POK
12
11
C81
R2
59k
10
9
8
7
C4
4.7µF
3
2
1
Buck Enable
3
2
1
LDO Enable
GND
GND
R3
100k
VOUTLDO
1
POK
Figure 5: AAT2505 Evaluation Board Schematic.
Thermal Calculations
There are three types of losses associated with the
AAT2505 step-down converter: switching losses,
conduction losses, and quiescent current losses.
Conduction losses are associated with the RDS(ON)
characteristics of the power output switching
devices. Switching losses are dominated by the
gate charge of the power output switching devices.
At full load, assuming continuous conduction mode
(CCM), a simplified form of the step-down converter and LDO losses is given by:
IQBUCK is the step-down converter quiescent current and IQLDO is the LDO quiescent current. The
term tsw is used to estimate the full load step-down
converter switching losses.
For the condition where the buck converter is in
dropout at 100% duty cycle, the total device dissipation reduces to:
PTOTAL = IOBUCK2 · RDSON(H) + IOLDO · (VIN - VOLDO)
+ (IQBUCK + IQLDO) · VIN
PTOTAL =
IOBUCK2 · (RDSON(H) · VOBUCK + RDSON(L) · [VIN - VOBUCK])
VIN
+ (tsw · FS · IOBUCK + IQBUCK + IQLDO) · VIN + IOLDO · (VIN - VOLDO)
Since RDS(ON), quiescent current, and switching
losses all vary with input voltage, the total losses
should be investigated over the complete input
voltage range.
1. For step-down converter, enhanced transient configuration C8 = 100pF and C1 = 10µF.
18
2505.2006.06.1.1
AAT2505
Dual Channel, Step-Down
Converter/Linear Regulator
Given the total losses, the maximum junction temperature can be derived from the θJA for the
TDFN33-12 package which is 50°C/W.
TJ(MAX) = PTOTAL · ΘJA + TAMB
PCB Layout
The following guidelines should be used to ensure
a proper layout.
1. The input capacitor C2 should connect as
closely as possible to VP and PGND, as shown
in Figure 4.
2. The output capacitor and inductor should be
connected as closely as possible. The connection of the inductor to the LX pin should also be
as short as possible.
2505.2006.06.1.1
3. The feedback trace should be separate from
any power trace and connect as closely as
possible to the load point. Sensing along a
high-current load trace will degrade DC load
regulation. If external feedback resistors are
used, they should be placed as closely as possible to the FB pin. This prevents noise from
being coupled into the high impedance feedback node.
4. The resistance of the trace from the load return
to GND should be kept to a minimum. This will
help to minimize any error in DC regulation due
to differences in the potential of the internal signal ground and the power ground.
5. For good thermal coupling, PCB vias are
required from the pad for the TDFN paddle to the
ground plane. The via diameter should be 0.3mm
to 0.33mm and positioned on a 1.2mm grid.
19
AAT2505
Dual Channel, Step-Down
Converter/Linear Regulator
Step-Down Converter Design Example
Specifications
VOBUCK = 1.8V @ 400mA (adjustable using 0.6V version), Pulsed Load ΔILOAD = 300mA
VOLDO = 3.3V @ 300mA
VIN
= 2.7V to 4.2V (3.6V nominal)
FS
= 1.4MHz
TAMB
= 85°C
1.8V Buck Output Inductor
L1 = 3
µsec
µsec
⋅ VO2 = 3
⋅ 1.8V = 5.4µH
A
A
(use 4.7µH; see Table 1)
For Sumida inductor CDRH3D16, 4.7µH, DCR = 105mΩ.
ΔIL1 =
⎛
VO
V ⎞
1.8V
1.8V ⎞
⎛
⋅ 1- O =
⋅ 1= 156mA
L1 ⋅ FS ⎝
VIN ⎠ 4.7μH ⋅ 1.4MHz ⎝
4.2V ⎠
IPKL1 = IO +
ΔIL1
= 0.4A + 0.068A = 0.468A
2
PL1 = IO2 ⋅ DCR = 0.4A2 ⋅ 105mΩ = 17mW
1.8V Buck Output Capacitor
VDROOP = 0.1V
COUT =
3 · ΔILOAD
3 · 0.3A
=
= 6.4µF; use 10µF
VDROOP · FS
0.1V · 1.4MHz
IRMS =
(VO) · (VIN(MAX) - VO)
1
1.8V · (4.2V - 1.8V)
·
= 45mArms
=
L1 · FS · VIN(MAX)
2 · 3 4.7µH · 1.4MHz · 4.2V
2· 3
1
·
Pesr = esr · IRMS2 = 5mΩ · (45mA)2 = 10µW
20
2505.2006.06.1.1
AAT2505
Dual Channel, Step-Down
Converter/Linear Regulator
1.8V Buck Input Capacitor
Input Ripple VPP = 25mV
CIN =
IRMS =
1
⎛ VPP
⎞
- ESR · 4 · FS
⎝ IOBUCK
⎠
=
1
= 4.75μF
⎛ 25mV
⎞
- 5mΩ · 4 · 1.4MHz
⎝ 0.4A
⎠
IOBUCK
= 0.2Arms
2
P = esr · IRMS2 = 5mΩ · (0.2A)2 = 0.2mW
AAT2505 Total Losses
PTOTAL =
IOBUCK2 · (RDSON(H) · VOBUCK + RDSON(L) · [VIN - VOBUCK])
VIN
+ (tsw · FS · IOBUCK + IQBUCK + IQLDO) · VIN + (VIN - VOLDO) · IOLDO
=
0.42 · (0.725Ω · 1.8V + 0.7Ω · [4.2V - 1.8V])
4.2V
+ (5ns · 1.4MHz · 0.4A + 50µA +125µA) · 4.2V + (4.2V - 3.3V) · 0.3A = 395mW
TJ(MAX) = TAMB + ΘJA · PLOSS = 85°C + (50°C/W) · 395mW = 105°C
2505.2006.06.1.1
21
AAT2505
Dual Channel, Step-Down
Converter/Linear Regulator
VOUT (V)
Ω)
R1 (kΩ
Ω)
R1 (kΩ
Adjustable Version
(0.6V device)
Ω
R2 = 59kΩ
Ω1
R2 = 221kΩ
0.8
0.9
1.0
1.1
1.2
1.3
1.4
1.5
1.8
1.85
2.0
2.5
3.3
19.6
29.4
39.2
49.9
59.0
68.1
78.7
88.7
118
124
137
187
267
75.0
113
150
187
221
261
301
332
442
464
523
715
1000
VOUT (V)
Ω)
R1 (kΩ
Fixed Version
R2 Not Used
0.6-3.3V
0
L1 (µH)
4.7
4.7
4.7
4.7
4.7
4.7
4.7
4.7
4.7
4.7
4.7 or 6.8
10
10
L1 (µH)
4.7
Table 3: Evaluation Board Component Values.
Manufacturer
Sumida
Sumida
MuRata
MuRata
MuRata
Coilcraft
Coilcraft
Coiltronics
Coiltronics
Coiltronics
Coiltronics
Part Number
Inductance
(µH)
Max DC
Current (A)
DCR
Ω)
(Ω
Size (mm)
LxWxH
Type
CDRH3D16-4R7
CDRH3D16/HP100
LQH32CN4R7M23
LQH32CN4R7M33
LQH32CN4R7M53
LPO6610-472
LPO3310-472
SDRC10-4R7
SDR10-4R7
SD3118-4R7
SD18-4R7
4.7
10
4.7
4.7
4.7
4.7
4.7
4.7
4.7
4.7
4.7
0.90
0.84
0.45
0.65
0.65
1.10
0.80
1.53
1.30
0.98
1.77
0.11
0.23
0.20
0.15
0.15
0.20
0.27
0.117
0.122
0.122
0.082
4.0x4.0x1.8
4.0x4.0x1.8
2.5x3.2x2.0
2.5x3.2x2.0
2.5x3.2x1.55
5.5x6.6x1.0
3.3x3.3x1.0
4.5x3.6x1.0
5.7x4.4x1.0
3.1x3.1x1.85
5.2x5.2x1.8
Shielded
Shielded
Non-Shielded
Non-Shielded
Non-Shielded
1mm
1mm
1mm Shielded
1mm Shielded
Shielded
Shielded
Table 4: Typical Surface Mount Inductors.
1. For reduced quiescent current R2 = 221kΩ.
22
2505.2006.06.1.1
AAT2505
Dual Channel, Step-Down
Converter/Linear Regulator
Manufacturer
MuRata
MuRata
Part Number
Value
Voltage
Temp. Co.
Case
GRM219R61A475KE19
GRM21BR60J106KE19
4.7µF
10µF
10V
6.3V
X5R
X5R
0805
0805
Table 5: Surface Mount Capacitors.
2505.2006.06.1.1
23
AAT2505
Dual Channel, Step-Down
Converter/Linear Regulator
Ordering Information
Voltage
Package
Buck Converter
LDO
Marking1
Part Number (Tape and Reel)2
TDFN33-12
Adj.
2.8V
POXYY
AAT2505IWP-AQ-T1
TDFN33-12
Adj.
2.6V
PPXYY
AAT2505IWP-AO-T1
All AnalogicTech products are offered in Pb-free packaging. The term “Pb-free” means
semiconductor products that are in compliance with current RoHS standards, including
the requirement that lead not exceed 0.1% by weight in homogeneous materials. For more
information, please visit our website at http://www.analogictech.com/pbfree.
Legend
Voltage
Adjustable
(0.6V)
0.9
1.2
1.5
1.8
1.9
2.5
2.6
2.7
2.8
2.85
2.9
3.0
3.3
4.2
Code
A
B
E
G
I
Y
N
O
P
Q
R
S
T
W
C
1. XYY = assembly and date code.
2. Sample stock is generally held on part numbers listed in BOLD.
24
2505.2006.06.1.1
AAT2505
Dual Channel, Step-Down
Converter/Linear Regulator
TDFN33-12
2.40 ± 0.05
Detail "B"
3.00 ± 0.05
Index Area
(D/2 x E/2)
0.3 ± 0.10 0.16 0.375 ± 0.125
0.075 ± 0.075
3.00 ± 0.05
1.70 ± 0.05
Top View
Bottom View
Pin 1 Indicator
(optional)
0.23 ± 0.05
Detail "A"
0.45 ± 0.05
0.1 REF
0.05 ± 0.05
Side View
0.229 ± 0.051
+ 0.05
0.8 -0.20
7.5° ± 7.5°
Option A:
C0.30 (4x) max
Chamfered corner
Option B:
R0.30 (4x) max
Round corner
Detail "B"
Detail "A"
All dimensions in millimeters.
2505.2006.06.1.1
25
AAT2505
Dual Channel, Step-Down
Converter/Linear Regulator
© Advanced Analogic Technologies, Inc.
AnalogicTech cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in an AnalogicTech product. No circuit patent licenses, copyrights, mask work rights,
or other intellectual property rights are implied. AnalogicTech reserves the right to make changes to their products or specifications or to discontinue any product or service without notice.
Customers are advised to obtain the latest version of relevant information to verify, before placing orders, that information being relied on is current and complete. All products are sold subject to the terms and conditions of sale supplied at the time of order acknowledgement, including those pertaining to warranty, patent infringement, and limitation of liability. AnalogicTech
warrants performance of its semiconductor products to the specifications applicable at the time of sale in accordance with AnalogicTech’s standard warranty. Testing and other quality control techniques are utilized to the extent AnalogicTech deems necessary to support this warranty. Specific testing of all parameters of each device is not necessarily performed.
AnalogicTech and the AnalogicTech logo are trademarks of Advanced Analogic Technologies Incorporated. All other brand and product names appearing in this document are registered trademarks or trademarks of their respective holders.
Advanced Analogic Technologies, Inc.
830 E. Arques Avenue, Sunnyvale, CA 94085
Phone (408) 737-4600
Fax (408) 737-4611
26
2505.2006.06.1.1